It’s now winter in Europe and many small birds are well on their way to warmer climes, migrating over large tracts of land in search of better weather. Along the way, they keep their course with a remarkable supersense – the ability to sense magnetic fields.
This sense is known as magnetoreception. It sounds like a party for an X-Men villain, and it’s also the subject of my latest feature, out in this week’s issue of New Scientist. I talk about how birds sense magnetic fields, using a compass in the eye and a map in the beak. I look at why the magnetic sense has been so fiendishly difficult to study and why it has taken five decades to unravel some of its details.
For the full details, you’ll have to read the feature, but this is the quick version: when light enters the eyes of birds, it excites a molecule called cryptochrome, shunting it into a state when it can be affected by the earth’s magnetic field. The upshot is that you can ‘blind’ a bird to magnetic fields by covering its eyes (and sometimes, just the right one). It’s possible that they may even be able to see the fields as patterns overlaid on top of their normal vision.
One of the reasons that magnetoreception is such a tricky topic (for scientists as well as science writers!) is that it straddles incredible diverse fields of research, including quantum physics, neuroscience and animal behaviour. Only a few scientists can bridge such divides, and I had the pleasure of interviewing two of them for my piece: Klaus Schulten and Thorsten Ritz. Both gave eloquent, insightful and funny interviews that were inevitably pared down into a few short quotes for the feature. Fortunately, I have all the space I need to make that material publicly available.
First up is Schulten, who talks with marvellous clarity about the early days of the research and where it expects it to go. He was warm and jovial, and gave a great insight into how discoveries are made – by connecting dots that no one else can see. I’ve edited it very gently for length, but the words are all his.